Randy Oliver writes:

“This was a rate of dispersal far slower than the AHB. Again, the 
geographical barriers surely played a part.”

    The geographical barrier issue would seem to be a significant one.  AHB 
has been for the most part traveling in parallel to the big mountain rages, 
while the movement of European bees would have been going perpendicular to 
them.  So we would need to look more closely to get an accurate picture of 
just how fast EHB is capable of spreading out before it encounters some 
geographical or climatologically barrier.  Never the less it’s clear that 
AHB is capable of expanding within its habitable range much more rapidly 
than EHB would be within its.  The rate of expansion of AHB, then, may only 
be useful in providing a benchmark in terms of how rapidly bees COULD 
travel on their own under suitable conditions.  Even scaling this top speed 
of AHB back for the EHB case I think we would get, under more or less ideal 
conditions, a potential rate of expansion of greater than 6 miles per year 
which is the top rate that Rury mentioned.  I realize that is kind of 
speculative on my part, but it’s a starting point.  
   All this has significance in terms of how rapidly parasites and diseases 
could spread over the continent or large sub regions of the continent if 
transporting bees could somehow be controlled.   What we are talking about 
here is how much time does trying to stop the unregulated human transport 
of bees, using enforcement measures, buy us, and is it worth the price we 
would have to pay.  It’s not clear to me.  This whole matter might 
eventually become moot if the rate of attrition of beekeepers in itself 
results in sufficiently less human transport of bees.
   

Steve Noble     

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